The neuropathologic examination of the brain provides unique information about possible factors contributing to clinical dementia. Diagnostically, it is the sole means of ascertaining the presence of neurodegenerative lesions and characterizing the type, extent and location of vascular changes. Operationally, the neuropathology core must provide information in a systemic and reliable fashion, while still meeting the needs of local investigators. Thus, the proposed neuropathology core combines standardized local neuropathologic assessment, with centralized quantitation of key neuropathological features. The specific aims of the Neuropathology Core are: 1) to provide standardized neuropathologic assessment and diagnosis for patients followed prospectively in the Central Coordinating Core, 2) to determine, using continuous rather than categorical analyses, how vascular lesions (infarcts and white matter changes contribute to dementia by themselves (size, location) and in combination with degenerative lesions (neurofibrillary tangles, senile plaques, cortical Lewy bodies), 3) to improve the clinical and pathological diagnosis of vascular dementia, and 4) to facilitate new research into the pathophysiology of vascular dementia. The core will provide tissue for projects 3 and 4, characterize the degree of neurodegenerative and cerebrovascular changes for all research projects, and will perform correlations of pre- and post-mortem data in conjunction with the Central Coordinating and Image Cores.